/Engine/Source/Runtime/RenderCore/Public/ShaderPipelineCache.h
Gets the event delegate to register to to be notified when currently viable PSOs have started to be precompiled from the cache.
static [FShaderPrecompilationBeginDelegate](API\Runtime\RenderCore\FShaderPipelineCache\FShaderPrecompilationBeginDelega-) & GetPrecompilationBeginDelegate()